In my U.S. Pat. No. 3,724,602, I describe one such hoist wherein the chassis lift may be coupled to the runway, so as to raise the runway therewith. The runways may be propped in an elevated position and the chassis lift uncoupled and independently displayed. Other multi-purpose hoists of a similar nature are also known in the art, for example where the runway is permanently connected to the elevator and the chassis lift may be coupled for elevation therewith or uncoupled as desired, this also using props for retaining the chassis lift when uncoupled.
In my U.S. Pat. No. 4,452,340, I described a multi-purpose hoist with co-axial elevating cylinders respectively connected to the runway and the chassis lift, which provides for independent operation of the runway and chassis lift without necessitating the use of props. Other hoists are also known wherein the runway is equipped with a built-in chassis lift, which may be otherwise referred to as a chassis jack which term includes a plurality of chassis jacks except where the context indicates otherwise. However, it appears that in each instance a separate motor means is provided for elevating the runway and each chassis jack. While this gives a desirable flexibility of operation it is a relatively expensive expedient.
It is an object of my invention to provide a multi-purpose hoist including a runway and chassis jack wherein the jack may be operated using the motion of the runway generated by the runway elevator.
It is another object of my invention to provide an economic multi-purpose hoist.
It is still another object of my invention to provide a multi-purpose hoist that does not rely on props.
It is yet another object of my invention to provide a multi-purpose hoist that is easily installed, maintained and operated.